Emesis is a neurologically mediated reflex act that serves as a protective mechanism, helping to remove ingested toxic or noxious substances from the gastrointestinal (GI) tract. Vomiting can be caused by primary GI, renal, or hepatic diseases, central nervous system (CNS) disorders, electrolyte changes, pancreatitis, and metabolic problems or may be due to ingestion of noxious substances. When ingestion of potentially toxic substance or foreign body occurs in companion animals such as dogs or cats, induction of emesis is often the first line of action. Intoxication as a result of oral exposure of poisonous chemicals, plants or human food (e.g. chocolate) is potentially a life threatening situation in dogs. Timely decontamination through use of emetics, serves in most cases to reduce systemic absorption acutely after exposure. Removing foreign body through emesis saves the dogs in many cases from endoscopic or surgical intervention.
Table salt is commonly used by owners even though it does not always induce emesis. Furthermore, large doses of table salt can cause serious hypernatremia. Orally administered hydrogen peroxide induces emesis in many dogs. Potential side effects of hydrogen peroxide are irritation of gastrointestinal tract, haemorrhagic gastritis, gastric dilatation volvulus and aspiration pneumonia. Historically also mustard powder, soap and syrup of ipecac have been recommended for use as an emetic agent, but are no longer standard of care due to side effects and lack of efficacy. Subcutaneously administered apomorphine has been used for induction of emesis in dogs. However, apomorphine has a disadvantage that it also exhibits anti-emetic effect mediated by opioid μ receptors in the vomiting centre in the brain. The side effects of apomorphine include prolonged vomiting, excitation, depression and local irritation. Apomorphine is contraindicated with medications that can result in respiratory or central nervous system depression. None of the existing approaches to induce emesis works reliably, and many have undesirable side effects. Further, no veterinary-labelled product is available that could be easily and safely administered by the animal owner at home.